Numerical evidence for a continuous phase transition between Neel and valence bond solid phases on a spin-ladder system

We investigate the possibility of deconfined quantum criticality in the J-Q-like model in one spatial dimension.
As the simplest example, we study a spin-1/2 two-leg XXZ ladder with a four-spin interaction by using the Variational Uniform Matrix Product State (VUMPS), which can directly calculate physical quantities in the thermodynamic limit.
We focus on the quantum phase transition between Neel and valence bond solid phases, which are characterized by breaking of SU(2) and space inversion symmetry, respectively.
We find evidence for a continuous phase transition between the two phases, which is unconventional according to the Landau-Ginzburg-Wilson paradigm.